FORM OF CONTRACT AGREEMENT
PUBLIC HEALTH WORKS
TECHNICAL SPECIFICATIONS (GENERAL)
TABLE OF CONTENTS
| |D E S C R I P T I O N |PAGE NO. |
|SR. NO. | | |
|SECTION-G |PLUMBING WORKS – GENERAL |2 to 5 |
|SECTION-1 |WATER SUPPLY WORKS |6 to 13 |
|SECTION-2 |PLUMBING & SANITARY WORKS |14 to 20 |
|SECTION-3 |SEWERAGE / DRAINAGE WORKS |21 to 28 |
|SECTION-4 | CONSTRUCTION OF MANHOLES |29 |
|SECTION-5 | STORM WATER DRAINAGE |30 to 31 |
|SECTION-6 |EXCAVATION FOR WATER SUPPLY LINE AND APPURTENANCES |32 to 36 |
|SECTION-7 |EARTH WORK FOR SEWER |37 to 43 |
|SECTION-8 |BEDDING |44 |
|SECTION-9 |DISMANTLING & RESTORATION OF PAVEMENT |45 |
|SECTION-10 |MISCELLANEOUS WORKS |46 to 47 |
|SECTION-11 |WATER RETAINING STRUCTURE |48 to 49 |
SECTION - G PLUMBING WORKS - GENERAL
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G-1 GENERAL
The stipulated therein, the direction as given below shall invariably be read with Section of the Special Provisions of the Contract.
The materials used and workmanship shall be of highest quality and grade and shall conform to the latest specifications of British Standards and Codes of Practice “Water supply “Sanitary Pipe Work” “Building Drainage” “Surface Water and Sub-Soil Drainage” and applicable to details and work indicated on the Drawings and Bill of Quantities or otherwise approved.
G-2 DRAWINGS AND INFORMATION REQUIRED
a). The Contractor shall submit shop drawings for the entire installation including installation details for all items required or asked for approval of the Consultants.
b). Approval by the Consultants of shop drawing for any material, apparatus, devices and layout, shall not relieve the Contractor from the responsibility of furnishing same of proper dimension, size, quantity and all performance characteristic to efficiently perform the requirements and intent of the Contract Documents. Such approval shall not relieve the Contractor from responsibility for errors of any sort in the shop drawing.
c). If the shop drawings deviate from the Contract Documents the Contractor shall advise the Consultants of the deviations in writing accompanying the shop drawings including the reasons for the deviation. At the start of the project the Contractor shall periodically and thereafter submit to the Consultants a list of all shop drawings which will be submitted in the course of the project. The list shall shown the disposition of each item including date of submission approval etc. The list shall be kept upto date through the entire course of construction.
G-3 CLEANING AND PROTECTION
a). The Contractor shall be responsible for his work until its completion and final acceptance, and shall replace any of the same which may be damaged, lost or stolen without any additional cost to the owner.
b). The opening left in floor for passage of lines of soil waste, vent and supply pipes shall be covered and protected.
c). The pipes shall be protected with suitable covering as soon as set. All open ends of pipes shall be closed by plug fittings to prevent obstruction and damage. The use of new permanent water closets and other new plumbing fixture during the progress of work is prohibited.
d). As soon as installed, all metal fixtures trimmings shall be thoroughly conversed by this Contractor with non-corrosive grease which shall be maintained until all construction work is completed.
e). Upon the completion of the work, the fixtures and trimmings shall be thoroughly cleaned and polished and left in first class condition.
f). Prior to delivering the plant to the Owner the Contractor shall thoroughly clean all equipment fixtures, fittings etc.
g). Before final connections are made and before operation of equipment and piping, all piping interior shall be thoroughly blow out, or washed out at least twice in a manner as directed by the Consultants remove all accumulation of dirt chips or other deleterious materials. Make all temporary connections and furnish all appliance required for the purpose of cleaning at no extra expense to the Owner.
h). Before erection. All pipes, tubing valves and fittings shall be thoroughly cleaned or oil, grease or other combustible materials by washing in a hot solution of sodium carbonate or tri-sodium phosphate mixed in the proportions of one pound to three gallons of water.
G-4 RECORD DRAWING
a). During construction the Contractor shall keep an accurate record of all deviations between the work as shown on the Contract Drawings and that which is actually installed.
b). The Contractor shall secure from the Consultants after approval of his Shop Drawings a complete set of drawings and note changes thereon in ink.
c). The Contractor shall make a complete record of all changed and revisions in the original design which exist in the completed work.
The cost of furnishing above prints and preparing these for record “shall be deemed to be included in the tendered cost and its effect spread over other items of work, and as such item shall not be a subject to payment” When all revisions showing the work as finally installed are made, the corrected Original Transparencies shall be submitted to the Consultants for review and delivered to the Engineer before final payment for the completed work will be made.
G-5 OPERATION AND MAINTENANCE INSTRUCTION
Three sets of operating and maintenance instruction covering completely the operation and maintenance of all plumbing equipment, controls, heats, pumps and the like shall be furnished to the Owners.
G-6 INSPECTION AND TESTING OF WATER MAINS AND WATER SUPPLY SYSTEM
Water Mains
The main should be tested in sections as the work of laying proceeds and joints should be left exposed for inspection during testing. After completion of each section, the main should be carefully and slowly charged with water so that all air is expelled, allowed to sand full of water for 1-2 days if possible and then tested under pressure. The test pressure should be 90M head or the maximum working pressure plus 50%, whichever is the greater.
The pressure should be applied by means of a manually operated test pump or, in case of long mains or mains of large diameter, by a power-driven test pump provided that the pump is not left unattended. Precaution must always be taken to see that in test pressure is not exceeded. Pressure gauges must be accurate and if necessary should be re-calibrated before the test.
After the pump has been stopped, the test pressure should be maintained as long as is necessary to inspect the whole of the pipe work under test and in any event not less than half-an-hour. Open ends of mains should be temporarily closed for testing under moderate pressure by fitting watertight expanding plugs. The end of the main and any test plug must be well secured to resist the end thrust of the water pressure in the main, i.e maximum test pressure x cross sectional area of pipe. If the section of main terminates with a sluice valve, the wedge of the valve should never be used to retain the water because this might lead to permanent distortion of the working parts of the valve. Instead the valve should be fitted with a blank flange or socket plug and the valve left in the open position whilst testing. End support should be provided as explained previously.
Cold Water Systems
When the installations are complete they should be slowly and carefully charged with water, allowing all air to escape thus avoiding shock or water hammer. The system should be inspected under working conditions of pressure and flow and when all draw-off taps are closed, should be absolutely watertight. Each draw-off tap should be opened and tested for rate of flow certain specifying authorities may require pressure testing of internal pipe work in which case, systems should be tested in accordance with the pressure test previously described. In such cases it may be necessary to isolate items of equipment from the pressure test if they are not capable of withstanding the test pressure. Where these items are removed, blanking flanges or plugs must be used or a make-up piece of pipe work installed temporarily.
All piping, fitting and appliances should be inspected and checked for satisfactory support and protection from physical damage corrosion and forest.
Because of the possibility of damage in transit, it is always advisable to re-test cisterns, tanks and cylinders for water-tightness on arrival at site and before fixing.
Hot Water Systems
Hot water system should be thoroughly flushed out and then tested in the same manner as described for cold water system. Where thermal insulation is used, the hydraulic test should be made before the insulation work is completed and whilst all joints are exposed.
Where a pressure test is employed, boiler and calorifier relief valves should be removed and these valves should be tested later. The test pressure should be one and half times the normal working pressure and this should be maintained for thirty minutes after making good any leaks.
It is necessary to carry out the hydraulic pressure test on sections of pipe work prior to completion of the whole installation where these are fixed in ducts, chases, trenches, etc. and are concealed from view. If rectification of faulty materials of workmanship on such sections is likely to involve disturbance to finished structural features, the test pressure should be twice the normal working pressure.
Sterilization of Cold Water Systems
The whole of the system should be sterilized to eliminate possible traces of bacteria.
Sterilization of public water mains is carried out by the Water Authority who may also carry out the sterilization of new private mains. Where this is not standard practice, the plumbing contractor should carry out the sterilizing process as descried below.
After cleaning the cistern of all debris, the cistern and pipe work should be filled with water and the whole thoroughly flushed out. The system should be then filled with water a second time, but as the cistern is filled, a sterilizing chemical containing chlorine should be added to ensure thorough mixing of the chemical and water. The dose should be such as to give 50 parts of chlorine to one million parts of water. If ordinary bleaching powder is used, the proportion should be 150g of powder to 1000 liters of water, the powder first being mixed with water to creamy consistency before being added. Proprietary brands of sterilizing chemicals should be added in the proportions as instructed by the manufacturers.
After filling the system, the incoming water supply should be shut-off and each tap on the distributing pipes opened successively, starting with that nearest the cistern. As the water which issues from each tap begins to smell of chlorine, the tap should be closed. The cistern should then be filled again to water-line with water to which has been added the correct dose of chemical.
The whole system should be allowed to stand charged with treated water for period of at least 3 hours, after which a test should be made by smell for residual chlorine. If none is found, the sterilization should be repeated.
Before any water is used for domestic purposes, the whole system must be emptied and thoroughly flushed out with clean water.
SECTION - 1 WATER SUPPLY WORKS
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1.1 DESCRIPTION
Work in this section shall include supply and installation of all the G.I pipe work upto 6” (150 mm) including all materials, plants, equipment, labour etc. to complete the work in close conformity wit the plans and in accordance with the provisions included herein.
1.2 MATERIAL REQUIREMENTS
All un-installed pipes and fittings used in the building work whether hidden in block/concrete work or running under ground shall be of Galvanized iron hot dipped in bitumen, wrapped around with bituminous Hessian with final two coats of brush applied bitumen.
It shall be ensured that the fittings shall be tested by jointing at least 5% of them to straight pipes in pipe vices with sufficient pressure, to the satisfaction of the Engineer. Defective fittings invariably crack on application of the pressure the fittings shall also be examined to detect blisters and minor cracks. The G.I pipe, fittings and specials shall conform to the following specifications:-
a). G.I Pipe
o BS-1387: Class-M
o Test Pressure = 700 psi
b). Malleable Iron (Galvanized Fittings (i.e. coupling, elbows, tees etc.) for G.I Pipes 2-1/2” and below shall be of at least same thickness and quality as G.I Pipe.
c). Cast Iron threaded flanges for joining G.I Pipe of dia 3” and above.
o BS-10 : 1962, Table D.
d). Cast Iron flanged fittings, for G.I pipe 3” and above.
o BS-2035, 1953: Class – B
o Working Pressure = 400 ft. of water.
e). Expansion Joints in G.I Pipes.
Adequate provision for expansion shall be provided on all pipe work as shown on the drawings. The Contractor shall obtain the Engineer’s approval for the materials being used for a particular expansion joint. Expansion loop for Horizontal G.I Pipe of dia 3” or below.
f). Cast Iron Sluice Valve (size 3” and above).
o Cast Iron body: Gummetal spindle and sealing rings.
o BS-3464, flanged BS-10; 1962
o Test Pressure = 225 psi
g). Copper alloy sluice valve (size 2-1/2” and below).
o BS-1952; threaded ends.
o Test Pressure = 225 psi
h). Cast Iron Check Valves (size 3” and above).
o Cast Iron body; Gummetal door.
o Test Pressure = 225 psi
i). Copper Alloy Check Valve (size 2-1/2” and below). Threaded ends Test Pressure = 225 psi
j). C.I Globe valves (size 3” and above). Similar to Cast Iron Sluice Valve.
k). Copper alloy globe valve (size 2-1/2” and below). Threaded, Test Pressure = 225 psi.
l). Fire Hydrant
Shall conform to BS: 750, with a body of Cast Iron and spindle of Manganese-bronze. The direction of closing shall be by Clock wise rotation and the outlet shall have screwed joints for accommodating 2-1/2” dia hose connection.
m). Double Air Valve
o Cast Iron Body
o Max. Working Head
Din 2 3 4 6
(in)
Head 200 575 575 575
(ft)
n). Pressure Reducing Valve.
The valve shall maintain a constant downstream pressure regardless of changing flow rate and / or varying inlet pressure. It shall be spring loaded, hydraulically operated, pilot-controlled diaphragm- type globe valve. The valve shall have a single removable seat and resilient disc. The body and cover of the valve shall be of cast iron for valves of size 3” or above and shall be of cast bronze for size 2-1/2” or below. The inlet and outlet of valve shall be threaded for size 2-1/2” or below and flanged for size 3” or above. The working pressure for valve shall be 175 psi minimum and the valve permit a convenient adjustment over a range of no less than 30 psi. the threaded valve shall be installed with two unions at its inlet and outlet end of facilitate its removal. All pressure reducing valve assemblies will be installed with bypass line having globe valve/gate valves so that removal of P.R Value for servicing/repair will not disturb the service of the circuit.
o). Strainer:
a). The straight cast iron strainer shall be installed on the submerged end of suction pipe drawing water from ground water from reservoir. The strainer flange shall conform to the specifications of BS 10, 1962. Minimum length of strainer for the specified dia shall be as follows:-
Dia Length
3” 5-11/16”
5” 7-1/2”
b). The strainer shall have cast iron or bronze bodies suitable to withstand the working pressure, removable screens of copper, brass, nickel or stainless steel flanged bodies with tappings for size 1-1/2” and above and of such a design as to allow blowing out of accumulated dirt and easy removal and replacement of strainer screen without disconnecting the main piping.
p). Puddle Plates:
Puddle plates of specified dia, shall be provided where G.I pipe crosses R.C.C wall retaining water or soil. 3/8” thick M.S square plate of size shown on plan cut with a hole equal to external dia of pipe, shall be welded with the pipe with both ends of G.I pipe provided with flanges, and the whole assembly shall be hot-dipped galvanized before being cast in R.C.C wall.
q). Float Valve, Level Controller, Flow Switch
Tender to provide Specifications of items locally available.
a). Float Valve
The float valve shall be direct float operated valve having globe body. The valve shall close drop-tight, at pre-set maximum water level, against pressures of upto 70 psi and shall open and close in direct proportion to rise or fall of water level.
The valve shall be of all brass construction with copper float and replaceable rubber seat and shall be furnished with threaded inlet and outlet ports of sizes 1-1/2” and below. For sizes 3” and above, the valve body shall be of cast iron with copper float, replaceable rubber seat and flanged ends.
The space available for the float valve, above maximum water level and location of valves shall be as shown in the Plans.
b) Liquid Level Controller
Liquid Level Controller, (float less type) comprising of control unit (for dual tank system) probe fittings complete with the electrodes and electrode holders suitable for operation on the Single Phase, 240V, 50Hz supply shall be employed wherever shown on the Plans. The controller shall have built-in surge arrestor. There guaranteed electrical life of the controller shall be 5x50000 operation minimum and the minimum tolerance of the rated voltage shall be + 15%
r). Pipe Sleeves for Cast Iron Pipes
The contractor shall supply and install the pipe sleeves in partition walls, RCC walls, slabs and other structural elements slabs). The pipe sleeves shall be located accurately and they shall be properly aligned and tied with the reinforcement bars so that the alignment and level is not disturbed during conboreting.
The RCC wall pipe sleeves shall be fabricated from corrected size Schedule 40 M.S pipe. M.S 3/8” thick sheet ring of sleeve size +6” shall be welded at the centre line of the sleeve to anchor the sleeve in RCC structure. After fabrication, the sleeve shall be heavily galvanized before installation. The inner galvanized surface shall be smooth.
RCC slab pipe sleeves shall be of construction as above but fabricated from 3”, 4”, 5” and 8” dia Schedule 40 M.S pipes and anchor ring shall be of 9-1/2”, 10-1/2”, 11-1/2” and 14-1/2” dia respectively.
s). Pipe Seal for Cast Iron Pipes
All exterior openings provided for the passage of piping shall be properly sealed with snugly fitting collars of metal or other approved rat-proof material securely fastened into place.
1.3 CONSTRUCTION REQUIREMENTS
1.4 EXCAVATION & REFILLING OF TRENCHES FOR PIPE WORK
The trenches shall be set out to suit alignment of the pipe lines. The trenches shall be carefully trimmed at sides and bottom compacted so that pipe lines when laid shall rest on the natural bed throughout the length. Shallow joint holes being left for the joint, where necessary. Where pipe line is to be laid in plains the depth of Cover, i.e the normal distance from ground level to other top of the pipe be kept at about 80 cm (2’-9”) and shall not be less than 75 cm (2’-6”) except due to special reasons the Engineer directs in writing to the contrary. The maximum depth of trench shall be taken as shown under:-
|I |II |III |
|For pipes upto & |For pipes 50 mm |For pipes over |
|including 38 mm |to 75mm (2” to 3’ |75mm (3”) dia |
| | | |
|50 cm Depth |50 cm Depth |60 cm Depth |
|(20”) |(22”) |(24”) |
After the pipes have been laid, jointed and tested and proved to be water tight the trench will be filled in 15 cm (6”) layers compacted and watered as required. Before that 6” thick sand cushion shall be provided around the pipe.
The various materials excavated to be separated and stacked, so that in refilling they may be again related in the same order, and thus least possible damage be done to public roads, cultivated field etc.
1.5 JOINTING SCREWED JOINTS
1.6 LAYING & JOINTING G.I PIPES
All screwed joints, shall be examined before jointing to ensure that the threads are perfect. In case of any flaw proper dies be used to make threads before they are jointed. The screwed ends of the pipes or specials to be jointed shall be very slightly tapered so that as the joint is screwed up, the threads shall bind together more and more tightly to ensure water tightness. The jointing work shall be so arranged in case of every joint that the two ends of pipes or specials jointed hereby shall be equidistant from the middle of the socket and shall have a space of not more than about a quarter of an inch between them in the centre of the socket. Before any joint is made all burs from the ends of the threaded joints shall be removed. For ensuring tightness against leakage telfon thread tape shall be used in all joints. For this purpose, hemp or jute or any material other than that described above shall not account be allowed to be used. The pipe shall be screwed up tightly with pipe fitter’s tongs or wrenches to ensure that each and every joint is perfectly water tight against the test head of water.
1.7 FLANGES
Flanged joints shall be provided at intervals of not more than 152 m (500 Ft.). Each flanged joint shall be made by inserting an accurately cut disc of tough multiply rubber insertion about 3.2 mm (1/8 mm) thick of approved quality between the flanges. The bolt holes in the rubber insert as well as in the flanges shall be drilled to template the bolts and nuts for all flanged joints shall consist of British Standard mild steel, hexagonal, round and hexagonal. The bolts shall be pulled up gradually and evenly by the use of standard spanner, so as to ensure a perfect joint.
1.8 BENDS, TEES AND OTHER SPECIALS
Bends, tees and reducers and other specials shall be provided and jointed at points as shown on the drawings or as directed by the Engineer. All changes in direction shall be effected by means of bends wherever practicable and the use of elbows shall be restricted only to cases where there in no room for bends in such cases only round elbows will be allowed.
1.9 TEST
All pipe lines in course of or after laying and jointing but before being covered, shall be tested hydraulically, using a test pump fitted with accurate pressure gauge to be approved by the Engineer to test pressure of at least 1.5 times their normal operating pressure. All pipes, specials and fittings with their joints shall remain perfectly water tight under the full test head for a period of not less than two hours after the whole length of the pipe line has been examined and demonstrated to be water tight.
1.10 PIPES ATTACHED TO WALLS OR CEILINGS
a). Provide suitable and substantial mild steel duly enamel coated hangers and supports for all horizontal and vertical line of approved type and make special vibration eliminating and flexible hanger shall be provided for all pipe work affected by moving machinery or expansion and contraction including building expansion joints.
b). Hot and Cold horizontal piping shall be supported in accordance with the following schedule.
| |Pipe Size Spacing |Minimum Hangers |Road Size |
| | | | |
|1- |1-1” and smaller |8 feet – 0 inch |3/8” |
|2- |1-1/4”-2 inch |9 feet – 0 inch |3/8” |
|3- |2-1/2-4” inch |10 feet – 0 inch |1/2" |
|4- |6” and larger |12 feet – 0 inch |1/2” |
c). Hanger shall be supported from approved concrete inserts in concrete slabs for all pipes 2” and above. Insert shall be as approved by the Engineer, and shall have space for nuts of all size. All inserts shall have a reinforcing rod of specified diameter to be installed through slot provided for this purpose, and the Contractor shall be responsible for its being in place when concrete is poured. The Contractor shall place all inserts in pour for all pipes which are to be hung, in ample time to allow the Contractor for general consideration to perform his work on schedule. If any pipe has to be hung is space where no inserts have been provided, the Contractor shall drill holes from below through concrete slabs and provide rods and hangers attached to not less than two approved type expansion shield each one capable of taking full maximum load. The rods and complete hangers shall be of adequate size to support the load which they carry.
d). Provided approved roller supports, floor stands wall brackets, masonry, etc. for all lines running above the floors, and which can be properly supported by the floors of wails. Pipe lines near walls may also be hung by hangers, carried from approved wall bracket at a higher level than the pipe.
e). No piping shall be hung from the piping of other trades or other ripping except for small water branches in toilet where no other practical means of support can be found, in which case specific approval of the installation shall be obtained from the Engineer. Hangers shall not be fastened by means of vertical expansion bolts. Hanger shall be of heavy construction suitable for the size of pipe to be supported. All materials, except roller shall be a malleable iron or steel. Rollers shall be cast iron. Hanger shall be swirel split ring, wrought pipe clamp, or adjustable type or as approved.
f). Special care shall be taken in the placing of hangers at the top, bottom and in offsets of hot water risers, so as to allow for expansion of the vertical piping. Vertical risers shall be securely supported from the building construction by means of pipe clamps at every floor, or as too short to connect to the building construction.
g). For cast iron hub and spigot pipe and fittings hangers shall be provided on not more than 5 feet centres or a minimum of one hanger per each length of pipe. Where excessive numbers of fittings are installed between hangers, the Contractor shall provide additional hanger or reinforcing as required and to the satisfaction of Engineer. Securely anchor fittings to the building construction changes of direction to eliminate all horizontal movement. The Contractor shall furnish and install steel channels and angles for piping support. These support will be required at those floors which are not slabbed over and/or where the building structure is not directly useable for pipe support.
1.11 PIPE SLEEVE
Every pipe line laid through any RCC wall, ceilings or roofs shall be arranged to pass through proper hot dipped galvanized sleeve pipes as approved by the Engineer or ample diameter embedded therein to enable the pipe lines to pass easily and freely. The length of every such sleeve pipe shall be of full width or thickness of the wall and in the case of roof, ceiling or floor, shall be at least 4 cm (1-1/2”) longer than the thickness thereof and shall project to that extent above the upper surface unless the Engineer orders to the country.
1.12 INSULATION FOR HOT WATER LINE S
All hot water lines shall be insulated with sectional fibre glass insulated properly wrapped by 4 ounce canvas in the approved manner and as directed by the Engineer. The hot water circulation and hot water main and branches of sizes 2” and above shall be insulated with 1 inch thick insulation, while all other hot water pipes and fixtures branches shall have minimum thickness of 1/2" insulation.
All fibre glass insulation shall be of sectional type having a minimum density of 4 lbs. per Cft.
After insulation, buried or embedded hot water pipes and branches, shall be warped with bituminised hessian with final two coats of brush applied bitumen to make the entire insulated piping totally water proof. All pipes insulation exposed to the sun shall protected with G.I cladding.
1.13 DISINFECTION FOR WATER SUPPLY
After the testing of the pipe work has been satisfactorily completed and when approved by the Engineer, the Contractor shall disinfect the pipe lines by dispensing chlorine solution through the entire pipe network to obtain a minimum chlorine content of 50 mg/litre for a contact period of at least 30 minutes. The procedure and equipment used to introduce, disperse and test the chlorine in the pipe shall be subject to approval by the Engineer.
1.14 MEASUREMENT
The pipe work 150 mm (upto 6” dia) shall be measured in running foot and no separate measurement will be done for tees, bends, elbows, unions and other fittings. Unit of measurement for pipe work shall be taken along the centreline and unit of measurement will be one linear Ft.
1.15 RATE AND PAYMENT
The rate shall all cost of material i.e. pipe, fittings, jointing material, lubricant, sleeve pipes, hangers and clamps, fibre glass insulation and labour of every type and incidentals.
SECTION - 2 PLUMBING AND SANITARY WORK
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2.1 DESCRIPTION
Work under this Section includes supplying and fixing al sanitary works including English type W.C , squatting, or Asiatic W.C wash hand basins, urinals sinks, low down and high level cistern, automatic flushing tank showers, Taps, Valves and Fire Hydrant. Also any special fixtures called for on the plans and mentioned in the Bill of Quantities.
2.1.1 Material Requirements
2.1.2 Plumbing Fixtures and Fittings
1. European type water closet of not less than 19” (475 mm) clear opening between flushing rims in white earthenware best quality (local made) “P” or “S” trap 3 gallons (13.5 litres) enamelled, wall type flushing tank, enamelled flush bend, PVC symphonic type fittings complete with corrosion resistant alloy ball valve of best quality manufacture in Pakistan. Standard seat and cover with PVC rings and nuts and rubber buffers, etc. complete.
2. Asia/Orrisa type water closet of not less than 19” (475 mm) clear opening as measured between flushing rims with raised foot rest in white earthenware best quality (local made) with back or front flush, specified dia. C.I trap of the same make, 3 gallons (13.5 litres plastic/ceramic cistern flushing tank plastic ball value of Asia or equivalent 1-1/4” (31 mm) dia telescopic flush C.P. pipe of the same size fixed to wall with PVC/C.P/ saddle.
3. Wash basin of specified size in white colour earthenware best quality mounted on C.I brackets fixed to wall, (local made) with ½” (15 mm) C.P pillar cock, 1-1/4” (31 mm) C.P waste chain plug, local made heavy counter sunk screws, C.P waste pipe with bottle trap, ½” (15 mm) C.P type cock heavy duty with 1/2" (15 mm) C.P inlet connection ½” (15 mm) C.P brass union nuts washers, including pedestal 2 coats of approved enamel paint to C.I brackets.
4. Urinal size 17” (425 mm) in white earthenware best quality (local made) with pull/push valve globe valve chrome plated.
5. The shower roses shall be chromium finish universal type with adjustable spray of best quality local made as approval.
6. The sink shall be of stainless steel best quality local made with all accessories as shown on drgs.
NOTE
1. European type W.C Asian type W.C Wash Hand Basin and Urinals shall be approved make.
2. C.P brass waste and union 1-1/2” 1-1/4” (38 mm / 31 mm) dia with PVC / C.P down pipe to be provide for sinks and wash hand basins.
2.1.3 Showers
The shower head shall be chromium plated with fountains of size specified in the BOQ or as approved by the Engineer.
Each shower shall be connected through a control valve to the hot and cold mixing valve. This shall be best quality manufactured approval shall be given by the Engineer.
2.1.4 Taps
All taps shall be of heavy duty type, chromium plated or brass as applicable and be of approved manufacture.
2.1.5 Gas Heating Equipment
The gas water heater shall be gas fired, direct, storage type with dual wall construction and be made of galvanized steel sheet. The heater shall be furnished with 1” dia drain pipe at bottom.
Electric water heaters, wherever specified, shall be direct type, fitted with electric immersion element and ¾” dia drain plug. The body of heater shall be made of galvanized steel sheet.
The gas and electric water heater shall be locally manufactured and be able to sustain working pressures upto 50 psi without any leakage. The rated heat capacity of all the heating equipment in terms of BTU per hour or KW shall be such as to raise temperature of volume of water equal to the specified capacity of heater, by 55 degree centigrade, in one hour.
The heaters shall be furnished with temperature indicator, thermostat to control switch ON/OFF operation and pressure relief valve.
The Contractor shall submit following information about heating equipment, before installation.
a. Manufacturer’s Technical Bulletin.
b. Storage capacity (gallons), rated heat input capacity (BTU per hr/kW), Thermal efficiency etc.
2.1.5.2 Thermostat Control Water Mixer Unit
Wherever indicated on plans, thermostatic control water mixer unit shall be installed on hot and cold water pipes, near outlet of water heater to control the temperature of supply at source. The mixer unit shall be import quality and made of stainless steel. The mixer unit shall operate satisfactorily for the following ranges of temperature.
Output Temperature 41-45 Degree centigrade
Input Temperature
Hot Water 55-60 Degree centigrade
Cold Water 10-20 Degree centigrade
The Contractor shall submit manufacturers technical bulletins, for the suggested mixer unit, for approval.
2.1.6 Hose Steel Cabinet
The hose cabinet shall be of 18 gauge heavy stock steel with joint. The face of cabinet metered, welded, ground finish and smooth with no visible seems or joints on face to cabinets. All joints shall be electrically welded. Doors to be furnished with full face wired plate glass panel, removable and secured with extruded vinyl glazing finish hinges shall be special alloy forged bronze, finished to exterior of cabinet. Knobs shall be semi-recessed, cam action latch, forged bronze with chrome plate finish set in stainless steel cup. No screw or bolts heads shall be used on face of cabinet. All concealed surface of cabinet shall be prime coated after fabrication to prevent corrosion. All interior exposed surfaces shall be finished in baked enamel to be confirmed by the Architect through Engineer for colour scheme the exterior shall be prime coated and left in condition for finished painting. Cabinet shall be surface mounted as indicated or approved. The cabinet includes Hose-pipe 100 feet length with brass nozzle and coupling complete in all respects. The Cabinet includes 2-1/2” dia canvas hose pipe of 100 feet length, properly joined with hydrant on supply end and with 1” dia brass nozzle on discharge end. The hole assembly including hose pipe shall be tested for a minimum test pressure of 140 psi.
2.2 CONSTRUCTION REQUIREMENTS
2.2.1 Water Closets
The work shall consist of providing and fixing in position squatting type water closet or European type water closet of an approved manufacturer white/light coloured (Prime/Export Quality). The squatting type pan shall be of white vitreous China, glazed fire, fire clay, or any other approved non-absorbent material with specified diameter trap of the same material and foot rest. The surface shall have a glazed finish with minimum of fouling area and a seal depth greater than 50 mm. The outlet shall be placed well back and the pan shall be sufficiently long to meet the design requirement. The flushing water connection shall be from the rear end.
The European type water closet shall also be of vitreous China made of an approved manufacturer with low level flushing cistern and with double seat cover. The W.C shall be of syphonic type with large water area and deep seal. The cleaning being effected by syphonic action. It shall have a low trap at the floor line so that the closet can not be un-trapped by the empting water.
The low level flushing cistern shall be of 13.6 litres capacity of Ceramic as specified in the BOQ. The Cistern shall be provided with a corrosion resistant alloy or plastic ball value with float of dia not smaller than 100 mm and an additional 13 mm cock and shall be provided with an over-flow pipe at least one size larger than the supply pipe, with a minimum internal diameter of 18 mm and it shall be fixed on mild steel or cast iron cantilever brackets, if required and as shown on the Plans.
The flush pipe shall be ‘plastic’ PVC or chromium plated steel pipe the holes for inlet, outlet and overflow in the cistern shall be made water tight by inserting rubber washes or other means of providing a water fight joint. The position of water closet shall be so arranged that it shall not face Qibla.
Every water closet shall be provided with a water supply bin tap for filling the small water cans in the site down position. A chromium plated toilet holder close to each water closet also be installed.
2.2.2 Sink
Sink shall be of enamelled iron or 18 gauge stainless steel of size as specified in the BOQ with self-contained drain boards of approved manufactures. The sink shall be fitted with rubber plug and washers, 38 mm dia chromium plated bottle or S trap with waste pipe with all necessary accessories for making the sink a complete units. The internal angles shall be of a design to facilitate cleaning with a fall towards outlet to drain the contents completely.
2.2.3 Service Sink
If required shall be made of stainless steel of 16 gauge as approved by Engineer. The sink shall be used for drawing water for scrubbing and cleaning and to dispose off the contents of scrub buckets and vessels containing slops. The edge of the sink shall be placed about 600 mm above the floor to minimize lifting and to leave room for the trap beneath.
The water supply and drainage equipment for such sinks shall be similar to that for kitchen sinks, except that no hot water supply or mixer will be installed.
2.2.4 Water Pump
Pumps for Domestic Water, Fire Fighting, Drainage and Sewage Lift Station
The centrifugal pump-motor sets shall be heavy duty industrial type suitable for continuous and quiet operation.
The centrifugal pumps shall be single stage, small size of vertically split casting and large sizes of horizontally split casing as specified in the Schedule of Equipment.
The pumps to be volute type, cast iron body, fully bronze fitted, bronze impeller of radial type with double curvature vanes, stainless steel shaft or shaft sleeve, properly lubricated bearings, readily accessible stuffing box with packing and seal cage, flanged suction for the pump and the motor and the pump shafts covered with approved guard, pump casing to be complete to be completed with drain and vent plugs and designed, tested and proven tight for a test pressure at least equal 1.5 times the maximum working pressure.
The pumps to have the gate valves and strainers on the suction side, globe valves on the discharge side and pressure gauges on suction and discharge sides. If pumps are operating in parallel then a check valve to be installed on the discharge side of each pump.
The pump shall be direct driven by a constant speed motor and provided with a suitable starter. The pump motor HP has been given for each system for guidance but it is intended that motor of higher HP shall be provided in required to ensure that it is not overloaded under any possible operating conditions of the pump.
Each pump shall be guaranteed for circulating the specified water quantity against specified net discharge head under the specified conditions of operation when operating continuously without overheating the motor, bearings, etc. However, the CONTRACTOR will check and confirm the actual discharge head required before placing orders for the pumps.
The pump shall be selected for quiet operation so that pump noise is not audible outside the plant room. The pump sound shall not be transmitted to the Building Structure.
The pumps installed for one system should be suitable for parallel operation in all respects. The pump impeller and motor should be so selected that these are not overloaded when only one pump is operating and increased water flow is to be handled due to reduced system head.
The CONTRACTOR shall supply anti-vibration foundation material (Both pads for isolator of main foundation and spring mountings for inertia mass) for isolating the pump foundation from the Building Structure.
The number, size and conditions of operation for pumps required for different systems are specified in the Scheduled of Equipment and the pumps location shown in the drawings.
Certified performance data and curves shall be submitted by the Contractor for approval to confirming the purchase order on the manufacture / supplier.
The Tender to give following information for the pump.
a). Pump capacity in Usgpm against net discharge head, PRM, HP of motor, and pump maximum HP requirement.
b). Construction and other technical details.
c). Overall dimensions and operating weight.
d). Manufacturer’s Performance Guarantee Certificate and performance data and curves and technical bulletin.
The sewage ejector sub miserable centrifugal pump motor sets shall be vertical heavy duty Industrial type with non-clogging impeller suitable for continuous operation.
The pump capacity rating shall be as specified in the Schedule of Equipment.
The pump shall be vertical single entry single stage non self-priming. The pump casting shall be radially split open towards the discharge end sealed off by a cover, suction end with a renewable wear plate and nozzle, impeller suitable for mixture of contaminated fluids, solid particles and sludges. The shaft length shall suit the installation depth shown in the drawings and shaft pieces joined together by threaded shaft coupling. The weight of the rotor and axial thrust will be absorbed by deep grooved ball bearing in the vertical hollow shaft motor. A grease pump mounted on the pump mounting plate shall continuously feed grease individually to every bearing during pump operation. The pump shall be fixed with soft packed stuffing box fed with sealing grease, the pump base plate shall be sized large enough to enable the pump to be pulled out/lowered in to the pit without the necessity of enlarged pit roof opening. The pump discharge line will be terminated above the base plate. The wear plate shall be of cast iron, shaft protecting sleeve of stainless steel, shaft of carbon steel, base plate of steel, motor stool of steel/cast iron and bearing of lead bronze.
The pump motor sets to be of local manufacture, KSB type KVP or approved equal.
Level Controllers
Each group of the above pumps shall have a control system as detailed below:-
A three position level controller shall automatically control the pump operation. The level controller shall the pump at high level and stop the same at low level. A highest level, the level controller shall energise an audio – video alarm.
2.2.5 Unions
Provide accessible unions in supply and return connections at all equipment fixtures, fixtures, specialist automatic valves, screwed end valves and at all other points in the system where required, in order to facilitate removal of specialities or equipment for repairs.
2.2.6 Expansion Joints for C.I Soil or Waste Pipe
Expansion joint in C.I soil or waste pipe shall be provided as pre plans, where the pipe crosses building expansion joint. These will be of non-pressure type, similar to imported Jossam Series.
2.3 MEASUREMENT
Measurement shall be made for the number of fixtures and toilet accessories acceptably provided and fixed in position.
2.4 RATE AND PAYMENT
Payment shall be made for the number measured as provided above at the contract unit rate for the respective items in the Bill of Quantities and shall constitute full compensation for all labour, material, use of equipment and tools required for work related to the item including providing and fixing all other work to complete. The item in all respects as specified or as directed by the Engineer.
SECTION - 3 SEWERAGE / DRAINAGE WORK
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3.1 DESCRIPTION
3.1.1 Sewerage Pipes
All sewerage/drainage pipe work inside the house and buildings and upto connection to the trunk sewer shall be covered under this section. The pipe shall be R.C.C or C.I as specified including soil, waste, vent and snit-syphonic pipes.
3.2 MATERIAL REQUIREMENTS
All RCC/C.I/UPVC pipes shall conform to the specifications referred to in Section.
“Material” and as specified in this section.
For Cast Iron Pipes, the joints shall be lead caulked. The packing material shall be pure jute, hemp or hemp yarn. All exposed C.I pipes and fittings shall be painted with 2 coats of black enamel over one primer coat.
For RCC pipes the cement mortar to be used on joints shall be of 1:1 ratio or as per plans alongwith rubber ring. Material specifications for sewerage and drainage shall be as follows:-
a). Cast Iron spun pipe, socket and spigot (6’ length)
o Minimum Weights
Dia (in) 2 3 4 6
Weight (Lb.) 24.9 37 48 72
o Test Pressure against leakage = 20 psi
b). Cast Iron Fittings
o Minimum Weight (Lb.)
TABLE – 1 (BENDS)
|Fittings (Inches) |2 |3 |4 |5 |
| | | | | |
|87-1/2 degree and 45 degree Bend without access |6.8 |11 |15 |24.9 |
| | | | | |
|87-1/2 degree and 45 degree Bend with access 29.9 7 | | | | |
|11.9 18 29.9 | | | | |
| | | | | |
TABLE – (WYES & REDUCERS)
|Fittings (Inches) |2x2 |2x3 |3x3 |2x4 |3x4 |4x4 |
| | | | | | | |
|87-1/2 degree and 45 degree |9 |15 |16 |17 |20 |24 |
|without access | | | | | | |
| | | | | | | |
|87-1/2 degree and 45 degree |11 |16 |18 |20 |24 |26 |
|Why with access | | | | | | |
| | | | | | | |
|Electric Reducer with smaller side |- |7.9 |- |11 |11 |- |
|socketted | | | | | | |
| | | | | | | |
c). R.C.C Pipe
o BSS 556 : Class – M < 9”
o 6” dia pipe with collar
o 9” pipe, spigot and socket
o ASTM C76-72-a > 12”
3.2.1 Cast Iron Floor Trap, Manhole Frames and Cover, Grating
These shall be cast from a mixture of cast iron scrap and suitable grade of pig-iron, and resultant metal shall be of strong grey structure, free from chips, air bubbles and sand holes and shall be smooth and even both inside and outside.
3.2.2 Grease Trap
Grease Trap shall be made of cast iron, for specified flow capacity and inlet/outlet dia and provided where shone on plans. Grease trap shall be embedded in raised floor and inlet shall be submerged.
3.2.3 Glazed Earthen Ware
Shall be of best and approved quality and the water seal shall not be less than 63.5 mm (2-1/2”) deep.
3.3 CONSTRUCTION REQUIREMENTS
3.3.1 Laving of RCC Pipe
Pipes and accessories shall be carefully examined before being laid and defective damaged pipes shall not be used. The pipes shall be brushed clean inside and outside to remove any soil or foreign matter that may have accumulated, including inside of the sockets and outside of spigots, before being lowered into the trench, and shall be kept clean during laying operation by plugging or other approved method.
The bottom of the trench shall be shaped to give substantially uniform circumferential support to the lower fourth of each pipe. Pipe laying shall proceed upgrade with the spigot ends of the bell and spigot pipe pointing in the direction of flow. Each pipe shall be laid true to line and grade and in such manner as to form close, concentric joint with the adjoining pipe. if the width of the trench at the pipe is exceeded than necessary, due to any reason other than under direction from Engineer, the Contractor shall install at no additional cost to the Owner, such concrete cradling pipe encasement or other bedding as may be required to satisfactorily support the added load of the backfill.
Trenches shall be kept free from water until the pipe jointing material has set, and pipe shall not be laid when the condition of the trench or the weather condition is unsuitable for such work. At times when work is not in progress open ends of pipe and fittings shall be securely and satisfactorily closed so that no trench water, earth, or other substance will enter the pipe and fittings.
As the work progress, the interior of the sewer shall be cleaned of all dirt and superfluous materials of every description. Where cleaning after laying is difficult because of small pipe size, a suitable swab or drag shall be kept in the pipe and pulled forward past each joint immediately after the jointing has been completed.
Where sewers cross above water line the sewer pipe for a distance of 3 metre (10 feet) each side of the crossing shall be of cast iron steel or other acceptable pressure pipe and with no joints closer than 3 feet (900 mm) to the crossing, or shall be fully encased in concrete of min. 15 cm. (6”) thickness.
Any section of the pipe found to be defective before and after laying, shall be replaced with sound pipe without additional expense to the Owner.
The jointing or pipes with collars shall be done first with spun yarn rope (dipped in hot maxphalt composition) fitted in between the ends of pipes and pressed together. The dia of rope shall not exceed 19 mm (3/4”) or as directed by Engineer.
The collar shall then be brought in the middle of the joint. Wooden wedges shall be placed at two or three places around the pipe so that the collar may have uniform gap all round the pipe for pressing pipes together. At a time five or six pipe shall be jointed together. Alter putting bitumen soaked hemp rope, suitable jacks and wedges or any other approved method shall be use. The inside of the collar and outside portion of the pipe shall be cleaned with brush and cement mortar of 1:1 proportion shall then be inserted from both ends of the collar. The mortar containing as little quantity of water as possible shall be carefully inserted by hand into the joints and tightly pressed with caulking tool. The mortar shall be finished off on the outside at an angle of 45 degree. The wooden wedges shall be carefully removed and mortar filled in the cavity before finishing. The joints shall be protected form weather and maintained wet for a at least ten days and shall not be covered with backfill until the joints have been tested and approval given by the Engineers.
For jointing of pipes with spigot and socket joints, the first pipe shall be bedded with the socket end upstream. The interior surface of the socket shall be carefully cleaned with a wet brush and its lower portion filled with mortar to such a depth as to bring together the inner surfaces of the abutting pipes flush and even. All further joints shall be made in this manner. The remainder of the socket joint shall be filled in with mortar and well pressed with the help of caulking tool. The mortar shall be finished smooth on the outside at an angle of 85 degree. The joints shall be protected and cured as for collar joints.
3.4 SOIL, WASTE, VENT AND ANTI-SYPHONIC PIPES
Examination and preparation of pipes shall be as for RCC pipes.
The pipes shall run exposed or embedded in walls and floors as specified or shown on drawings. Where embedding in walls or floors is required, the necessary instruction and route of pipe work shall be approved by the Engineer. Pipes running exposed on walls and ceiling shall be properly clamped with Hangers, supports and clamps for passage of pipes through masonry wall and RCC beams, slab and walls, pipe sleeves shall be embedded and properly caulked and water proofed.
Horizontal soil and waste pipes unless otherwise specified shall be given a grade of 6.4 mm (1/4”) and 3.2 mm (1/3” 1/ft.) respectively. All main vertical soil stacks shall extend full size to above the roof line, except where otherwise indicated. The part of the soil stacks carried up as vent pipe shall not have any bend or angle except when unavoidable, in which case, the angle shall be as obtuse as possible. The vent stack shall joint the soil stack at a point not less than 3 feet (900 mm) above the highest connection to the soil stack. Horizontal waste lines receiving the discharge from two or more fixtures on the first floor shall be provided with end vents, unless separate venting of fixtures is called for.
Changes in pipe size on soil, waste and drain lines shall be made with reducing fittings or recessed reducers. All changes in direction shall be made by the appropriate use of 45 degree Wyes, long or short sweep 3 mm to 1.5 mm bends etc. or equivalent fittings as approved. Single and double sanitary tees and quarter bends may be used in drainage lines only where the direction of flow is from horizontal to vertical. Short sweep not less than 75 mm (3”) in diameter may be used where the change in direction of flow is either in plan or vertical to horizontal and may be used for making necessary offsets between the ceiling and the next floor above. The use of short sweep bends or fittings, where deemed necessary because of installation conditions, shall be subject to the approval of the Engineer.
Contractor shall provide offsets in the piping where required or directed by the Engineer to avoid interference with other work, or to increase the headroom under piping, or to improve the appearance of the pipe work. Piping shall be installed in such a manner that will permit freedom of movement during expansion and contraction without causing the pipes to be warped and adequately insulated against noise transmission through pipe work in habitable rooms.
All piping shall be installed in such a manner as to prevent delay or interference with the work of others working in the same area. All openings in pipes shall be kept closed during construction work with plugs.
Slip joints shall be permitted only in trap seals or on the side of the traps. Tucker or hub drainage fittings shall be used for mating union connections wherever practicable. The use of long screw and bushing is prohibited.
Clean-out shall be of the same size as the pipe except that clean-out plugs larger than 100 mm (4”) will not be required. Clean-outs installed in connection with cast iron spigot and socket pipe shall consist of a long sweep ¼” bend or one or two 1/8” bends extended to any easily accessible place, or where indicated on the drawings. An extra heavy cast-brass ferrule with outer sunk trap screw cover shall be caulked into the hub of the fitting and shall be flush with the floor. Where clean-outs in connection with threaded pipe and indicated and are acceptable, they shall be cast iron drainage T-pattern 90 degree branch fittings with extra-heavy brass screws plugs of the same size as the pipe upto and including 100 mm (4”). Test tees with cast iron clean-out plugs shall be installed at the footing of all soil, waste, and drain stacks and on each building drain outside the building. In addition, clean-outs shall be provided at all changes of direction in excess of 45 degree, and at distance not exceeding 15 meter (50 feet) in horizontal drain line 100 mm (4”) and smaller size, and not exceeding 30.480 mm (100 feet) in drain lines larger than 100 mm (4”). Underground clean-outs shall be extended to an accessible location, to the surface of the floor above, or to grade, subject to approval of the Engineer. Panels and plates for access to clean-outs shall be provided.
Each fixture and piece of equipment, including floor drain, requiring connections to the drainage system shall be equipped with a trap. Traps are to be supplied with the fixtures. Each trap shall be placed as near to the fixtures as possible, and no fixture shall be double-trapped. Except as otherwise indicated traps installed on bell and spigot pipe shall be cast iron. Traps installed on threaded pipe shall be recess drainage pattern.
3.5 FLOOR TRAPS
Floor traps with gratings shall be made of high grade, strong, tough, and even grained metals, Castings shall be free from blow holes porosity, hard spots, excessive shrinkage cracks, or other defects shall be smooth and well cleaned both inside and outside. Castings shall not be repaired, brazed, or burned. The wall thickness of iron casting shall be not less than 6.4 mm (1.4”).
Joints for Cast Iron soil, waste and vent pipes shall be made with lead, jute, hemp or hempen spun yarn. The packing material shall be well placed into the annular space so as to prevent the entrance to lead into the pipe. Run lead joints shall be applied to perfectly dry pies. Under wet condition lead fibre joints shall be made both with quantities and depth of jointing material and by method as per B.S Code C.P. 301 (1950). The remainder of the space shall be filled with molten lead that is hot enough to show a rapid change in colour when stirred. The lead shall be caulked to from a tight joint without ever straining the bell.
3.6 TESTING OF PIPELINES
No work shall be covered over or surround with concrete until it has been inspected, tested and approved by the Engineer.
3.7 INSPECTION AND TESTING OF DISCHARGE PIPES
Work would be inspected and tested during installation, care being taken that all work which is to be concealed is tested before it is finally enclosed. Final tests should be applied on completion of the installation both for soundness and performance. Normally, the air test is used for soundness, but if the water test is applied, it should be used only up to the level of the lowest sanitary appliance connected to the system, and then only in new system.
When testing old system, it may be necessary to limit the pressure applied because of shallow trap seal; the water test should not be used. Any defects revealed by the test should be made good and the test repeated until a satisfactory result is obtained.
Reference: should be made to Local Authority and other enforcing authority requirements, particularly where pipe work passes through areas where blockages and leaks cannot be detected. In general, sufficient access should be provided to enable complete systems to be tested.
Access points should be carefully sited to allow the entry of cleaning and testing equipment and consideration also be given to adjacent services. Traps and joints that are easily disconnected can be an advantage so additional access is required only under exceptional circumstances.
The discharge from urinals can give rise to heavy deposits, specially in hard water areas. Regular maintenance is therefore required and access should be provided so that all parts of the stack, branch, discharge pipe and trap can be readily cleaned. Where the vertical discharge pipe has a long connection to a manhole, access should be provided at ground floor near the foot of the stack.
In multi-storey domestic building, access should be provided at 3 storey intervals or less. In public and commercial buildings and more complex, drainage systems, access should be provided at each floor level.
The discharge from appliance produces pressure fluctuations and the system must be designed to retain adequate water seal in all traps under excessive working conditions. Pressure effects that occur may be due to self siphonage or positive pressure. It may be necessary to use a ventilating pipe to limit the pressure fluctuations in the system within the acceptable limits.
The effect of the water from an appliance into a branch discharge pipe must be considered taking account of :
a) The design of the appliance (funnel shaped appliances increase the possibility of self siphonage).
b) The length, slope and diameter of the branch discharge pipe.
Seal losses produced by effluent flow down the discharge stack depend on :
a) The flow load which in turn depends on the number of appliances connected and frequency of use.
b) The diameter of the discharge stack.
3.5 Air Test
An air test should apply a pressure equal to 3.8 mbar (38 mm) (50 mbar (50 mm) Scotland) water gauge and should remain constant for a period of not less that three minutes (five minutes Scotland). The water seals of all sanitary appliance which are installed should be fully charged and a test plug inserted into open ends of the pipe work to be tested, each plug being sealed with a small quantity of water. One testing plug should be fitted with a tee-piece, with a cock on each branch, one branch being connected by a flexible tube to a manometer.
To apply the test, air or smoke is introduced into the system through the other branch of the tee-piece until the desired pressure is shown on the manometer scale. Alternatively, the pressure may be applied by passing a flexible tube from a tee-piece attached to a manometer through the water seal of the trap of a sanitary appliance, the test then being carried out as previously described.
Defects revealed by an air test may be located by the following :
a). A smoke producing machine may be used which will introduce smoke under pressure into the defective pipe work. Leakage can be observed as the smoke escapes.
b). Soap solution can be applied to the pipes and joints, under test, leakage can be detected by the formation of bubbles.
3.6 Performance of Testing System
In addition to a test for air or water-tightness, every discharge pipe installation should be tested for stability of the trap seals on the system. When subjected to the appropriate discharge test, every trap must retain not less than 25 mm of water seal. Each test should be repeated three times, traps being recharged before each test and the maximum loss of seal in any one test should be taken as the significant result.
The number of appliances to be discharged simultaneously for the test depends upon the number of appliances installed and the use and occupancy of the building. Suitable figures are given in Table C9 for dwellings. For other types of buildings e.g. hotels and hospitals, the service conditions lie somewhere between these two. The number of appliances to be discharged simultaneously to simulate these conditions should be estimated from the figures given in Table C9 the expected service conditions.
3.7 Dwellings
To test for the effect of self siphonage, waste appliances should be filled to over flowing level and discharged in the normal way. The seal remaining in the trap should be measured when the discharge is finished.
To test for the effects of probable maximum simultaneous discharges of sanitary appliances the number of appliances to be discharged together is given in Table C9. For the purpose of this test, baths are ignored as their use is spread over a period and they do not normally add materially to the peak flow.
Where a stack services baths only, the number to be discharged simultaneously in a test should be the same as for sinks. The worst conditions occur when appliance on the upper floors are discharged. A reasonable, test therefore is to discharge up to one WC, one basin and one sink from the top floor of the building with any other appliances to be discharged on the floor immediately below.
Table: C9 Number of appliances to be discharged simultaneously for testing stability of seals; Dwellings
|Number of Appliances |Number of Appliances discharged simultaneously |
|of each kind on the Stack | |
| |WC (9 Litres) |Wash Basin |Kitchen Sink |
|1-9 |1 |1 |1 |
|10-24 |1 |1 |2 |
|25-35 |1 |2 |3 |
|36-50 |2 |2 |3 |
|51-65 |2 |2 |4 |
RCC pipe below 300 mm dia shall conform to B.S 5911 Class-C and dia 300 mm or above the ASTM C76-88.
3.8 MEASUREMENT
All pipe work shall be measured in running foot of finished length. No wastage or length consumed in joints shall be measured for payment. Sockets, spigot and RCC collars shall not be measured separately.
For cast iron pipe line the length consumed in valves, fittings and specials shall be measured alongwith pipe line.
Cast Iron specials and fittings such as Tees, Tapers, Bends, Shoes, Crosses, Offsets, flanged sockets and spigot plugs and caps etc. shall be measured alongwith the pipeline.
3.9 RATE AND PAYMENT
The rate for all items under this section shall cover the cost of all materials, labour, tools, equipment and appliance and performing all operations for laying, fixing and jointing and all work as specified in accordance with drawings, Bill of Quantities and as directed by the Engineer. Rate for pipe work shall also include making and repairing cut holes and chases in walls, floors and slabs etc. painting pipes, supports and accessories cleaning and clearing pipe lines and testing till approved by the Engineer.
SECTION - 4 CONSTRUCTION OF MANHOLES
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4.1 DESCRIPTION
The work consist of constructing manholes for sewerage of positions shown on the plans or where otherwise directed by the Engineer and in accordance with the detailed drawings supplied from time to time, complete in all respect.
4.2 MATERIAL REQUIREMENTS
Brick masonry, Portland cement concrete, and other materials shall materials shall meet the specified requirement of the relevant sections of the specifications for RCC given Section – “Portland Cement Concrete” Manhole steps shall be of mild steel as shown on the drawings.
4.3 CONSTRUCTION REQUIREMENTS
Manholes shall be constructed with brick masonry of specified wall thickness lain din 1:4 sand cement mortar and RCC concrete slab. The cover slabs shall be Class-C reinforced cement concrete fitted with cast iron frame which shall have weight 1/2 CWT 18” (450 mm) diameter cast iron cover as shown in the plan. The inside of the walls shall be plastered with 1:4 sand cement mortar. At the bottom of manholes for sewers a proper channel as per drawings, shall be constructed in the whole length of the manhole along the centreline of the sewers, to lead the sewage from one sewer to the other. Mild Steel bar steps shall be installed inside the manhole, during the construction of the manhole walls. Cutting holes into the wall for the steps after construction will not be permitted. Top rung shall be 18” (450 mm) below the manhole cover and the lowest not more than 12” (300 mm) above the benching (Floor). Manholes shall have cement concrete Class-C benching as per drawings / specifications. Manholes shall be connected with the nearby sewerage manholes through a reinforced cement concrete pipe as per details provided. Manholes alongwith the central and primary drains shall also act as over-flow structures. The existing overflow pipes shall be securely connected with these manholes.
4.4 MEASUREMENT
Measurement shall be made for the actual number of manholes as shown in BOQs of the appropriate type constructed at site as per drawing and specifications laid down in this section and to the approval of the Engineer.
4.5 RATE AND PAYMENT
The unit rate quoted in the priced Bill of Quantities for the construction of manholes shall be considered full compensation to cover the cost of all materials including framework and concrete, brick masonry, excavation, backfilling, steps frame and cover, and connecting pipe with the manhole and all labour including curing, plastering, trenching, etc. and all incidentals to completely construct them at site, as per drawings and specifications laid down in this section.
SECTION - 5 STORM WATER DRAINAGE
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5.1 DESCRIPTION
The work under this section consists of all drainage work and related items necessary to complete the work indicated on the drawings and described in the specifications. The work includes but is not limited to the following:-
1. All storm water drainage piping shall be C.I or PVC within and RCC outside buildings as shown on the plans with connections to catch pits and open drains plus all related items to complete the work.
2. Provide all catch pits wherever shown on the drawings with C.I Grating and hinged grating (if required).
3. Provide C.I grating at the roof inlet of all vertical rain water drop pipes, as shown on the plans.
4. Gravel bedding shall be provided wherever called for on the drawings or directed by the Engineer.
5. Testing cleaning, adjusting and placing in operation all piping installed.
6. Pipe culverts of sizes indicated on the drawings.
5.2 MATERIAL
Materials for C.I and RCC pipe shall conform to the respective Specifications specified under Section-3.2. The PVC pipe shall conform to the requirements of BSS 3505, Class-B, for which the working pressure shall 87 psi minimum. The PVC pipes used shall be with integral parallel socket and shall be joined by solvent welding method.
5.3 CONSTRUCTION REQUIREMENTS
Construction Requirements of pipe work shall meet the relevant specifications appearing else- where in the documents.
5.3.1 Protection of Works
The installation shall be adequately protected against damage and deterioration particulate care must be taken during the course the course of construction of seal all open ends of pipe work with a temporary cover. Wood shavings or paper will not be accepted for this purpose.
5.3.2 Concreting of Pipes
Where pipes are laid below a building, roads or near the surface etc. they shall be in case in or protected with concrete as shown on the drawings. No pipe shall be concreted until the pipe has been to the satisfaction of the Engineer.
5.3.3 Catch Pits
Catch Pits shall be constructed of brick masonry with Plain Cement Concrete Class-D base of 4” thick. Catch pit shall be of the dimensions indicated on the drawings. Cast iron frame and grating shall be provided as indicated on the drawing directed by the Engineer.
5.3.4 Drains
Drains shall be provided in accordance with drawings. Brick drains shall be constructed of brick masonry with a Plain Cement Concrete Class-E base. Internal walls of the drain shall be plastered in a (1:4) cement sand mortar of thickness, shown on the plans.
Drains in concrete shall be constructed of Class-D concrete and shall be provided at positions and sizes shown on the drawings.
The drains shall be laid in straight lines and to slopes indicated on the drawings. They shall be kept free from mud debris, superfluous cement or other obstructions.
5.4 MEASUREMENT
All pipe work shall be measured in Running M/Ft. of finished length. No wastage or length consumed in joints shall be measured for payment. Sockets, spigot and RCC collars shall not be measured separately. Holder bats/sleeve pipes required for pipes attached to walls and ceiling gong through walls shall not be measured separately.
Measurement for drains shall be in Running M/Ft. Catch pits shall be measured for the number of catch pits acceptably provided.
5.5 RAE AND PAYMENT
The rate for all items under this section shall cover the cost of all materials, labour, tools, equipment and appliance and performing all operations for laying, fixing and jointing and all work as specified in accordance with drawings, Bill of Quantities and as directed by the Engineer. Rate for pipe work shall also include making and repairing cut holes and chases in walls, floors and slabs etc. painting pipes, supports and accessories cleaning and clearing pipe lines and testing till approval by the Engineer. Rate for catch pits, drains and piping shall include excavation backfilling masonry/concrete work, frame and hinges wherever called for, complete as per plans or directed by the Engineer.
SECTION - 6 EXCAVATION FOR WATER SUPPLY LINES AND APPURTENANCES
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6.1 DESCRIPTION
The work covered by this section of the specifications consists of furnishing at plant, labour, equipment, appliances and materials and performing all operation in connection with excavation, trenching and back filling for water lines and appurtenances in strict accordance with this section of the specifications and the applicable drawings, and subject to the terms and conditions of the contract.
6.2 CLEARING AND GRUBBING
The sites of all excavation shall be cleared of all shrubs, plants, bushes, large roots, rubbish and other surface materials. All such materials shall be removed and disposed off in a manner satisfactory to the Engineer. All trees and shrubbery that are designated by the Engineer to remain shall be adequately protected and preserved in an approved manner.
6.3 EXCAVATION
6.3.1 General
All excavation of whatever substance encountered shall be performed to the depths indicated or as otherwise specified. During excavation, material suitable for backfilling shall be stockpiled in an orderly manner at a sufficient distance from the banks of the excavation to avoid overloading and to prevent sides from caving. All excavated materials unsuitable or not required for back fill shall be removed and wasted at a location approved by the Engineer. Excavation in the streets shall be done in such a manner that street passage is not blocked by excavated material. Grading shall be done as may be necessary to prevent surface water from flowing into trenches or other excavations, and any water accumulated therein shall be removed by pumping or by other approved methods. Unless otherwise indicated or approved by the Engineer, excavation shall be open cut.
6.3.2 Trench Excavation
Unless otherwise directed or permitted by the Engineer not more than 500 ft. of any trench in advance of the end of the pipe line already laid shall be opened at any time, unless otherwise directed or permitted by the Engineer not more than 1000 ft. of any one trench shall be worked on at a time from removal of pavement bottom, not exceeding 5 feet in depth shall be a maximum of 20 inches plus the external diameter of the pipe barrel and the width of the trench exceeding 6 feet in depth shall be maximum 30” plus external diameter of the pipe barrel. The banks of the pipe trench shall be as nearly vertical as practicable. Bell holes and depressions for joints shall be dug after the trench bottom has been prepared. The pipe, except for joints, shall rest on the prepared bottom for its full length. Bell holes and depressions shall be only of such length, depth, and width as required for properly making the particular type of joints. Stones shall be removed to avoid point bearing. Whenever wet or otherwise unstable material that is incapable of properly supporting the pipe as determined by the Engineer is encountered in the bottom of the trench, such material shall be removed to the depth required and the trench backfilled to the proper grade with coarse sand, or other suitable approved granular material. Such replacement of unsuitable material shall be paid for at the contract unit price for that item of work. Trenches shall be of a depth to provide a maximum cover, over the top of the pipe, of 30” form the existing ground surface or finished grade whichever is closer except that trenches for pipe laid in lanes and alleys of narrow travelled way (average width of 8 feet) or less between structures) shall be of a depth to provide a minimum cover, over the top of the pipe of 18” from the existing ground surface or finished grade whichever is closer.
6.3.3 Excavation for Appurtenances
Excavation for appurtenances shall be sufficient t leave at least 12” but not more than 24” between the outer surface and the embankment or timber that may be used to hold and protect the banks any over-depth excavation below such appurtenances that has not been directed by the Engineer will be considered unauthorized and shall be refilled with compacted sand, gravel or concrete, as directed by the Engineer at no additional cost to the Owner.
6.3.4 Maintenance of Excavation
All excavation shall be properly maintained while they are open and exposed. Sufficient suitable barricades, warning lights, flood lights, signs and similar items shall be provided by the Contractor. The Contractor shall be responsible for any damage due to this negligence.
6.3.5 Removal of Water
The Contractor shall build all drains and do ditching, pumping, well pointing, bailing, and all other work necessary to keep the excavation clear of ground water, sewage and storm water during the progress of the work and until the finished work is safe from injury. All water pumped or drained from the work shall be disposed of in a manner satisfactory to the Engineer and necessary precautions against flooding shall be taken.
6.3.6 Sheeting and Bracing
If ordinary open-cut excavation is not possible or advisable, sheeting and braking shall be finished to the work and to provide working conditions which are safe. The Contractor shall finish and place all sheeting, shorting, wall braces, timbers and similar items, necessary for the safety of the work, the general public and adjacent property. Sheeting shoring and bracing shall be removed as the working progresses and in such a manner as to prevent damage to finished work and adjacent structures and property. As soon as withdrawn, all voids left by the sheeting and bracing shall be carefully filled with sand and compacted. The Contractor shall be fully responsible for the safety of work in progress, for the finished work, the workmen, the public and adjacent property.
6.3.7 Protection of Facilities
Existing subsurface facilities likely to be encountered during the execution of work require special precaution for the protection, such as sewers, drain pipes, water main, conduits and electric cables and the foundations of adjacent structures. The Contractor shall be responsible for the damage of any such facility and shall repair the same at his expense whether or not this facility has been shown on the drawings.
6.3.8 Surplus Materials
All surplus materials shall be disposed off at locations approved by the Engineer disposal of surplus material shall not interfere with other works and shall not damage or spoil other material. When it is necessary to haul earth or the material over street or pavement, the Contractor shall prevent such material for filling on the street pavement.
6.3.9 Cutting Pavement
In cutting or breaking street surfacing, the Contractor shall not use equipment which will damage the adjacent pavement. Existing paved surfaces shall be cut back beyond the edges of the trenches to form neat square cuts. The road ballast, brick pavement, and other materials shall be placed on one side and shall be preserved for re-instalment when the trench is filled. Wherever necessary or required for the convenience of the public or individual residents, at street crossings and at private driveways, the Contractor shall provide suitable temporary bridges over untilled excavation. All such bridges shall be maintained in service until backfilling has been completed. The Contractor shall keep the road crossings manned 24 hours per day. During night time, enough red lights shall be provided to warn traffic. If detour is necessary, the Contractor shall make proper detour for the traffic and shall install signs 3 feet by 4 feet in size indicated the detour.
6.4 BACKFILLING
The trenches shall not be completely backfilled until all required pressure tests are performed and until the water lines as installed conform to the requirements of specifications. Where in the opinion of the Engineer, damage is likely to result from withdrawing sheeting, shoring; the same shall be left in place and cut off at a level 12” below ground surface. Trenches shall be backfilled to the ground surface with selected excavated material or other material that is suitable for proper compaction. Trenches improperly backfilled shall be reopened to the depth required for proper compaction, then refilled and compacted to the specified density. The surfaces shall be restored to be original or better condition. Pavement and base course disturbed by trenching operations shall be required.
6.4.1 Low Portion of Trenches
Backfill material shall be deposited in 6” maximum thickness layers and compacted with suitable and hand tempers to ninety five percent of maximum density until there is a cover of not less than 12” over the water liens. The backfill material in this portion of trenches shall consist of sandy clay or other approved materials free from stones and humps.
6.4.2 Remaining of Trench
The remainder of the trench shall be backfilled with material that is free from stones larger than 6” in any dimension. Backfill material shall be compacted to 90 percent of maximum density for cohesive soils and 95 percent of maximum density for others.
6.5 BORROW
Where suitable material for backfill is not available in sufficient quantity from required excavations, suitable material shall be obtained from approved sources at the Contractor’s responsibility. The necessary clearing and grubbing or borrow areas, disposal and burning of debris there from, the developing of sources including any access roads for hauling and the necessary right-of-way, and the satisfactory drainage of the borrow shall be considered as incidental items to be borrow excavation.
6.6 GRADING
After completion of all backfilling operations, the Contractor shall grade the work areas to be lines, grades and elevation shown on the drawings. Finished grading shall not be done until the installation of all water lines has been completed and tested. The top surface after completion shall be “in level” to the adjacent existing surface. Prior to final acceptance, all damage due to settlement shall be repaired by and at the expense of the Contractor.
6.7 TESTING DENSITY OF SOIL IN PLACE
The Engineer may make tests using the calibrated sand cone method/core cutter method to determine the density of soil in place. If soil in place fails to meet the specified degree of compaction the areas represented by the failing tests shall be removed, replaced and compacted to the specified density in the manner directed by the Engineer and at no additional cost to the Owner.
6.8 MEASUREMENT
The measurement shall be made for the actual quantity of the work done in cube fee. The maximum width of the trenches allowed for payment for various pipe sizes will be as under:-
a). Upto 2” diameter pipe, the trench width will be 15”
b). Upto 3” diameter pipe, the trench width will be 18”
c). Upto 4” diameter pipe, the trench width will be 18”
d). Upto 6” diameter pipe, the trench width will be 21”
e). Upto 8” diameter pipe, the trench width will be 24”
f). Upto 10” diameter pipe, the trench width will be 26”
g). Upto 12” diameter pipe, the trench width will be 28”
h). Upto 16” diameter pipe, the trench width will be 32”
6.9 RATE
The unit rate tendered in the priced Bill of Quantities for excavation of trenches for water supply lines shall be considered as full compensation for the work specified in this section and shall include constructing and removing of all temporary arrangements pumping and dewatering, removal of soft soil from bottom of trenches, removing the surface material and all incidentals to complete this work.
6.10 PAYMENT
Payment shall be made for this item of work a the unit rate quoted in the priced Bill of Quantities.
SECTION - 7 EARTH WORK AND SEWER
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7.1 DESCRIPTION
Work under this section shall consist of furnishing all materials, equipment and labour for excavation, trenching and backfilling for sewers, drainage facilities structure and all other appurtenances of sewage collection system, in accordance with drawings to proper line and grade refilling the trenches and dressing them to proper surface.
7.2 CLEARING AND GRUBBING
The sites of all excavations shall be cleared of all shrubs, plants bushes, large roots, rubbish and other surface materials. All such materials shall be removed and disposed of in a manner, satisfactory to the Engineer all trees and shrubbery, that are designated by the preserved in an approved manner.
7.3 EXCAVATION
7.3.1 General
The Contractor shall do all excavation of whatever substance encountered to the depth shown on the drawings or as otherwise specified. Excavation shall include without classification the removal and disposal of all material of whatever nature that would interfere with the proper construction and completion of the work and shall include the furnishing, placing and maintenance of supports for the sides of the excavation. The work shall also include all pumping, ditching, dewatering and other measure required for the removal and exclusion of water. During excavation, material suitable for backfilling shall stock-piled in an orderly manner at a sufficient distance from the bank of the excavation to avoid over-loading and to prevent sides from caving. Top soil should be stockpiled separately for subsequent reuse as necessary. All excavated material suitable or not required for backfilling shall be removed and disposed of at a location approved by the Engineer.
For contract purposes hereunder, the earth excavation work has been classified into two categories, earth excavation in trenches, and earth excavation for structures.
7.3.2 Earth Excavation in Trenches
Except as otherwise provided herein, excavation for a sewer line shall be open cut trenches with vertical side and not more than 150 feet of any trench in advance of the end of the built sewer shall be opened at any time and unless written permission to the Contractor is given by the Engineer. The trench shall be excavated to its full depth for a distance permitted for the sewer to be laid. Trenches for sewer-lines and appurtenances shall be to the lines and grades shown on the drawing or as ordered in writing by the Engineer as necessary for the proper completion of the work. Bell holes and depressions for joints shall be dug after the trench bottom has been graded. The pipe for joints shall rest on the prepared bottom for its full length. Bell holes and depressions shall be only of such length, depth and width as required for properly making the particular type of joint. Stones shall be removed to avoid point bearing.
Where the bottom of the excavation is in material which is the judgement of the Engineer by reason of its hardness cannot be excavated to provide a uniform bearing for the pipe, said material shall be removed to minimum of 6 inches below the grade of the bottom of the pipe, and the trench backfilled to the required pipe sub-grade with river sand or other material acceptable to the required depth with concrete grade if so ordered. In no case material removed from such excavation shall be used as backfill material unless approved by the Engineer. All instruction shall be in writing by the Engineer.
7.3.3 Earth Excavation for Structures
All earth excavation under this contract, which is not included under the classification of “Earth Excavation in Trenches” shall be classified and paid for as earth excavation for structures.
The Contractor shall provide adequate timbering or shoring for excavations. Should the sides and ends of any excavations give way the Contractor shall, at no extra cost, remove all disturbed ground. Any excavation carried outside the limits shown or drawings and specified herein as the payment limits, shall not be treated as excavation and shall not be paid for.
When foundation level is reached, the Engineer representative will inspect the exposed ground and give directions as to what further excavation, if any, be considers necessary. The excavation should be done in such a manner, as to ensure that the work rests in a solid and perfectly clean foundations. If the Contractor allows any portion of such foundations to deteriorate due to exposure, he shall make good the foundation to the satisfaction of the Engineer without extra cost.
7.3.4 Alignment and Grade
The sewers are to be laid to the alignment and gradient shown on the drawings, but subject to such modifications as shall be ordered by the Engineer from time to time to meet the requirements of the works. No deviations from the lines, depths of cutting or gradients of he sewers shown on the drawings and sections shall be permitted except by express directions in writing of the Engineer.
7.3.5 Setting of Sight Rails
The sewers shall be constructed and laid to a true grade and in straight lines between curves as shown on the plan. The sewer shall be laid and constructed to their proper levels with the aid of suitable boning rods and sight rails which shall be fixed according to the requirement of the Engineer at interval not exceeding 10 feet and also by levelling along the invert with levelling instruments. The sight rail and boning rods shall be provided, fixed and maintained by the Contractor who shall also provide and maintain suitable levelling instruments and equipment and shall set the positions and levels of the sewers and either work according to the drawings and any instructions which he may receive from the Engineer all sight rails and posts shall be well seasoned deodar timber or ample size and strength. The rails and boning rods shall be suitably and accurately planned and no warped or otherwise defective or damaged sight rails or boning rods shall be used. Sight rails shall be secured to the posts by strong steel clamps to the approval of e Engineer and in such a manner that they shall be fixed as immovable, in relation to the correct liens and levels. All boning rods and sight rails shall have the centre line accurately marked thereon by a fine saw cut and shall be pointed black and white to the requirements of the Engineer. All boning rods shall suitably be showed with iron. At least for separate sight rails shaft always be maintained in correct level and alignment along the line of sewer at every place where construction work is proceeding and the alignment and level of the sight rails shall be checked by the level and line at least twice every day to ensure that no disturbance of interference of the alignment and level have taken place. Whenever required the Contractor shall erect and maintain such additional sight rails as the Engineer shall direct. The Contractor shall, at all times, see that his workmen or other unauthorized persons are not allowed, accidentally or otherwise, to tamper or interfere with sight or other alignment or level marks.
All bends and curves shall be set out mathematically in a manner or approved by the Engineer and the Contractor shall provide and maintain for the purpose such additional sight rail posts and other wrought and rough timber work, steel wire and other articles as the Engineer shall require from time to time.
6. Sheeting and Bracing
If ordinary open-cut excavation is not possible or advisable, sheeting and bracing shall be furnished and installed in excavation to prevent damage and delay to the work and to provide working conditions which are safe. The Contractor shall furnish and place all shoring, sheeting, wall braces, timbers and similar items necessary for the safety of work, the general public and adjacent property. Sheeting, shoring and wall bracing shall be removed as the work progresses and in such manner as to prevent damage to the finished work and adjacent structures and property. As soon as it is withdrawn all voids left by the sheeting and backing shall be carefully filled with selected material and compacted. The Contractor shall be fully responsible for the safety of work in progress, for the finished work, the workmen, the public expenses, as part of the work under the excavation items and at no extra cost.
7.3.7 Dewatering and Trenches
As part of the work under the excavation items and at not extra cost, the Contractor shall build at drains and do ditching, pumping, well-pointing, hailing and all other work necessary to keep the excavation clear of ground water, sewage and storm water during the progress of the work and until the finished work is safe from injury, the Contractor shall provide all necessary pumping equipment for the dewatering work, as well as operating personnel, maintenance, power etc. all at no extra cost. All water pumped or drained from the work shall be disposed of in a manner satisfactory to the Engineer. Necessary precautions against flooding shall be taken.
7.3.8 Maintenance of Excavations
All excavation made hereunder shall be properly maintained while these are open and exposed. Sufficient suitable barricades, warning lights, signs and similar items shall be provided by the Contractor. The Contractor shall be responsible for any personal injury or properly damage due to this negligence.
7.3.9 Protection of Existing Facilities
The Contractor shall take special care of existing sub-surface facilities likely to be encountered during the excavation for their protection, such as sewers, drain pipes water, main conduits, electric cables, communication cables and the foundations of adjacent structures. The Contractor shall be responsible for any damage to any such facility and shall repair the same at his expense whether or not the facility has been shown on the drawing.
7.3.10 Disposal of Surplus Excavated Material
All surplus material excavated by the Contractor shall be disposed of at locations approved by the Engineer. The disposal of surplus material shall not interfere with other works and shall not damage or spoil other materials. When it is necessary to haul earth material over streets or pavements, the Contractor shall prevent such material from falling on the streets or pavements.
7.4 BACK FILLING
7.4.1 General
After the completion of sewer line, drainage facilities foundations, walls and other structures below the elevation of the final grade all voids shall be backfilled with suitable materials specified below.
7.4.2 Backfilling for Structures
Backfilling operations for structures shall be performed as part of the Contractor’s work under the payment items for earth excavation and at no extra cost. Backfilling material for foundations, walls and other structures shall consist of excavated soil which is free from stones and hard clods not larger than 3 inches in any dimension, and also free from trash, lumber and other debris. Backfill material shall have enough moisture for proper compaction and shall be compacted in an approved manner to 90 percent of maximum density for cohesive soils and 95 percent of maximum density for cohesionless soils. Backfill shall not be placed against foundation walls earlier that 4 days after placing of concrete or brick masonry.
7.4.3 Backfilling for Trenches
After the sewers have been constructed and proved to be water tight as per direction of the Engineer the trench shall be backfilled. Utmost care shall be taken in doing this so that no damage shall be caused to the sewer and other underground utilities. After this has been laid the trench and other excavation shall be backfilled carefully in 6” layers with earth as approved by the Engineer, each layer being watered to assist in the compaction unless the Engineer shall otherwise direct.
7.5 MAXIMUM DENSITY DETERMINATION FOR COMPACTED SOIL
The maximum density of the soil shall be determined in accordance with the latest revision of “American Society for Testing Material (ASTM) Standard D 1557 Density Relations of Soils, using 15 lbs Rammer and 18 inches Drop”.
7.5.1 Testing Density of Soil
The Engineer may make tests using the calibrated sand cone method / core cutter method to determine the density of soil in place in accordance with ASTM Designation D 2558, latest revision. If soil in place fails to meet the specified degree of compaction the areas represented by the failing tests shall be re-excavated and compacted to the specified density in the manner directed by the Engineer at no extra cost.
7.5.2 Top Soil
Top soil which has been stockpiled during excavation shall be used for the top 6” of backfill, in locations as ordered by the Engineer. Top soil shall be saturated with water and after is has dried, shall be spread to the required final grade and of required density. The work shall be performed at no extra cost.
7.5.3 Proximity to Buildings
Where buildings in the opinion of the Engineer near excavation are likely to be affected, the Contractor shall provide proper shoring to protect such buildings in addition to timbering of trenches. The Contractor shall be required to leave timbering inside trenches if so required by the Engineer for protection of these buildings at no extra cost.
7.6 LENGTH OF TRENCHES IN ADVANCE OF CONSTRUCTION
Unless otherwise directed in writing by the Engineer of the work not more than 200 feet in advance of constructed or laid sewer shall be left open at my time. The trench shall, however, be excavated to full width to minimum length of 16 feet in advance of the constructed laid sewer unless otherwise directed by the Engineer.
7.7 DISPOSAL OF FILTH AND GARBAGE
No night soil filth and garbage met with during the excavation shall be allowed to be deposited on side of road / street so as to cause nuisance or obstruction to traffic. The same shall be disposed of by the Contractor to a place to the satisfaction of the Engineer.
7.8 DISPOSAL OF SURPLUS EARTH
The Contractor shall dispose of all surplus excavated materials not required to be used on the work. This shall include surplus earth after refilling and compaction.
7.9 TUNNELLING
7.9.1 Formation of Soil
Tunnelling shall only be permitted in strong hard and homogeneous, clay formation which are not likely to collapse under normal working conditions. The work shall not be permitted in running sand. In weaker formation such as mixture of clay and sand which are liable to collapse when exposed to atmosphere. The roof shall be protected by adequate timbering and shoring of roof and the walls, irrespective of any type of alluvial strata. If the tunnel is subject to any sort of traffic, it shall be provided with adequate timbering and shoring for its roof and walls.
7.9.2 Length of Tunnel
Normally the length of tunnel without adequate support shall not exceed 3’. This length shall, however, may be exceeded under the directions of the Engineer, where depth of tunnel below ground level is considerable to avoid any danger of collapse. The tunnel, however, shall be driven in longer lengths upto 150 feet, if drive casing is provided as the tunnel is being excavated.
7.9.3 Horizontal Boring Machines
When considered necessary by the Engineer, horizontal boring machines shall be employed for crossing sewers underneath highways and canals. Whenever such machinery is used, drive casing of steel pipes shall be drive to avoid any collapse of the tunnel.
7.9.4 Backfilling of Tunnel
Tunnels shall be filled in with sands or selected material as directed by the Project Manager.
7.10 MEASUREMENT
Measurement shall be made for the actual quantity in 3’ of excavated trenches. The maximum width of trenched allowed for payment will be as follows:-
a). Trenches not exceeding 6 feet in depth 24” plus external diameter of the barrel for pipe sewers.
b). Trenches exceeding 6 feet and not exceeding 12’ in depth, 30” plus external diameter of the barrel for pipe sewers.
c). Trenches exceeding 12’ in depth, 36” plus external diameter of the barrel for pipe sewers.
7.11 RATE
The unit rate tendered in the priced Bill of Quantities for excavation and back filling of trenches for sewer lines, shall be the full compensation for the cost of materials, labour, equipment, tools and all incidentals necessary completely to execute this items of work strictly as per specifications laid down in this section.
7.12 PAYMENT
Payment shall be made at the unit rate quoted in the priced Bill of Quantities.
SECTION - 8 BEDDING
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8.1 GENERAL
Wherever specifically called for the means of notes on the contract drawings or by written order of the Engineer the Contractor shall furnish and place sand or pea gravel bedding underwater lines, drain pipes and other structures as a separate item of payment.
8.2 SOUND OF BEDDING MATERIAL
Sand or pea gravel for bedding shall be from a source and of specifications approved by the Engineer.
8.3 PURITY AND STACKING
The sand and gravel shall be free from clay, salt, alkali, organic matter, shale, loam, soft flaky particles and other deleterious substance. It shall be stacked at the place designated by the Engineer and kept free form the admixture of deleterious materials mentioned herein.
8.4 PLACING OF BEDDING MATERIAL
The material for bedding shall be placed to the specified thickness and compacted rammers of approved weight.
8.5 MEASUREMENT
The measurement shall be made by volume for the actual quantity of the work done and the unit of measurement shall be one cubic feet.
8.6 PAYMENT
Payment for this item of work shall be made for the actual quantity of work done and as specified in this section, at the unit rate quoted in the priced Bill of Quantities.
SECTION - 9 DISMANTLING AND RESTORATION OF PAVEMENT
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9.1 DESCRIPTION
The work covered by this section of the specifications consist in furnishing all labour, equipment, appliances and materials and in performing all operations in connection with cutting and restoration of road/street surface and pavement, cut or damaged as a result of work accomplished under this contract, in strict accordance with this section of the Specifications and the applicable drawings, and to the satisfaction of the Engineer.
9.2 CUTTING OF ROAD/STREET SURFACE AND PAVEMENT
In cutting and breaking road or street surface and pavement, the Contractor shall not use such equipment and appliances which shall damage the adjacent surface. Existing paved surface shall be cut back beyond the edges of the trenches to form neat square cuts. The dismantled materials shall be placed on one side of the trench for reuse after backfilling, for the restoration of the road surface. Not more than 500 feet of continuous road/street surface shall be cut or disrupted at a time for laying the drains. The contractor shall take all safety measures against traffic hazards and shall provide proper diversion for the traffic where necessary. The diversion shall be indicated by suitable street signs 3 feet by 4 feet in size. During night enough red lights shall be provided to warn the traffic.
9.3 CUTTING IN EXCESS OF THE WIDTH OF TRENCH
The cutting of the road/street surfaces and pavement shall be limited to the width of the trench. Where the Contractor has cut the road surface or pavement in excess of the width of the trench, be shall not be paid for the excess cutting and the excess cutting and the excess cutting shall be restored by the Contractor at his own expenses
9.4 RESTORATION OF ROADS/STREET SURFACE AND PAVEMENT
After backfilling of trenches the cut road/street surface and pavement shall be restored as quickly as possible to original foundations and grade and line in such a manner as to acceptable surface for traffic. Intersections shall be restored within 24 hours after being cut.
SECTION - 10 MISCELLANEOUS WORK
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10.1 DESCRIPTION
The work covered by this section of the specifications consist in furnishing all labour, equipment, appliances and materials and in performing all operations in connection with providing water, sewerage and drainage and gas connections to the existing lines.
This section of the specifications is intended to cover all miscellaneous items which are not specifically called for in other sections of these specifications, Items shown or called for on the drawing, but not itemized herein, shall be furnished under the Conditions of this section and shall generally conform, as closely as possible to these Specifications unless otherwise directed by the Engineer.
10.2 MATERIAL REQUIREMENTS
10.2.1 Structural Steel
For screen, grating & I beam steel shall be carbon grade (ASTM A-36), minimum strength of which shall be 36,000 psi. Except where otherwise shown all structural steel shapes and sized shall be shown on the Plans.
The bar steps in sewage lift station O/H, U/G Reservoir manholes shall be malleable iron steps (galvanized), designed with non-solid tread and shall comply with BS 1247/75. The steps shall be hot dipped galvanized with overall length, width, tread length and minimum weight of 10, 6, 5 inches and 4.6 lbs. respectively.
10.3 CONSTRUCTION REQUIREMENT
10.3.1 Fabrication of Screen
Screen and gratings for sewage lift station shall be constructed in accordance with the details as shown on the Plans.
Metal shall be well formed to shape and size, with sharp line or angles. Shearing and punching shall leave clean, true lines and surfaces. Permanent connections shall be welded. The use of screws or bolts shall be avoided but where used, heads shall be counter sunk screwed on tight, and the threads nicked to prevent loosening. Necessary rabbits, lugs and brackets shall be provided so that work can be assembled in a neat and substantial manner. Thickness of metal and details of assembly and supports shall give ample strength and stiffness. All the work shall be installed in an approved and rigid manner, and where possible, shall be secured with galvanized bolts or welded where shown.
10.3.2 Painting
Screen surface shall received one coat of rust inhibitive metal primer to red lead paint for which no separate payment shall made to the Contractor.
10.3.3 Welding
Welding shall be continuous along entire line of Contract, except where spot welding is indicated on the drawings or is authorized by the Engineer. Exposed welds shall be ground smooth except otherwise directed by the Engineer.
4. Bolting
Bolting where permitted shall be done with proper size bolts. Nuts shall be drawn tight and threads nicked.
10.4 MEASUREMENT
Measurement for screen will be made for the actual work executed at the unit rate entered in Bill of Quantities. Bar steps shall be measured per unit acceptably placed in the wall completed and approved. All connections to the specified lines (i.e. water, sewerage and drainage) shall be Lump sum.
10.5 RATE AND PAYMENT
Payment shall be made at the unit rate stated in the Bill of Quantities. Such payment shall constitute full compensation for furnishing all materials equipment and labour including testing and all other incidentals necessary to complete the work according to the applicable drawings and directions of the Engineer.
SECTION - 11 WATER RETAINING STRUCTURE
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11.1 DESCRIPTION
The work covered by this section of Specification & consist of Construction of Overhead, Underground Water Tanks and Swimming Pool.
11.2 MATERIAL REQUIREMENTS
All materials such as cement, sand, aggregate & steel etc. shall conform to the specifications given in respective Section (Material) or given elsewhere.
11.3 CONSTRUCTION REQUIREMENTS
The Contractor shall carry out the work according to design/drawing/instructions of Engineer Incharge. Work shall include the following:-
1. Columns / pillar raised/constructed upto required height in RCC 1:1-1/2:3.
2. Bed and side walls of tanks shall be constructed in RCC 1:1-1/2:3 mixed with pudlo as per manufacturer’s directions.
3. Inside of the tank shall be finished with 1/2 thick terrazzo over ½” thick 1:2 cement sand mortar, or ceramic tiles as specified on drawings.
4. Roof slab shall be in RCC 1:2:4 with manhole cover with frame and vent pipes.
5. In joint water stopper 9” wide will be used.
6. For pipes, Rising mains, delivery, overflow and washout, puddle collars of specified size will be fixed during pouring of side wall concrete.
7. Necessary gauge and float valve shall be provided.
8. Stairs shall be provided inside & outside the tanks as per plans.
9. Inside of the tank will be lime washed for dis-infection.
10. If any where brick work is used, it will be 1st class brick work set in cement sand mortar 1:3.
11. If any plaster is done that will be in cement sand mortar 1:3 with pudlo.
12. External sides of walls of underground water tank will be provided vertical DPC as per Specifications in Section DPC
11.4 MEASUREMENT
Measurement will be taken in capacity of water tank. For calculating capacity Free board will not be accounted for i.e. height. Form bottom to water level will be taken.
11.5 RATE AND PAYMENT
Rate shall include all material form work & labour etc. complete in all respect as per design/ drawing/ instructions of Engineer Incharge.
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